The present invention relates to a hybrid circuit which performs two wire-four wire conversion in a trunk of an exchange, speech paths of various communication equipment and a line circuit of time-division multiplex communication equipment.
Conventional circuits of this kind are a hybrid transformer system and a resistance hybrid system forming a bridge of resistors. These conventional circuits have defects such that the output of an amplifier of the four-wire receive port is so consumed as to result in a loss, that a hybrid transformer is expensive and bulky, and that impedance balance is difficult.